Field of Invention
The present invention relates to a semiconductor device and a method of forming the same, and more particularly to a memory device and a method of forming the same.
Description of Related Art
Advancements in electronic devices lead to the need for greater storage capabilities. In order to satisfy the high storage density requirement, the size of a memory device is gradually decreased and the level of integration is accordingly increased. Therefore, the type of a memory device is developed from a two-dimensional planar gate structure to a three-dimensional vertical gate structure. One of vertical gate structures is a gate-all-around (GAA) structure.
In a three-dimensional device having a GAA structure, a higher local electric field is often observed at the corner of each bit line, and thus, the local charge storage uniformity is affected. Therefore, how to fabricate a three-dimensional memory device with an improved bit line shape has drawn high attention in the industry.